There is abundant epidemiological and experimental data to support the hypothesis that stress is a potent factor in the etiology of essential hypertension. However, there has only been a minimal amount of work addressing the elucidation of the mechanisms which underly stress-induced hypertension. The present research program is directed at providing a characterization of experimental stress-induced hypertension and to determine the contributing factors that produce and maintain this pathological state. The studies will employ an established multiple sensory stress paradigm which, until this time, has been employed primarily for studies on antihypertensive drug action. The proposed analyses will study the rat subjected to stressors during the labile and established phases of hypertension and will (1) characterize blood related factors that are potential contributors to the elevated blood pressure, (2) investigate the central neural and neurochemical substrates of this form of hypertension, and (3) ascertain the relative contribution of the sympathetic, humoral, and structural components to maintenance of the hypertension. It is expected that the results of the proposed line of research will lead to insights regarding basic mechanisms of hypertension induced by stress.